The present invention relates to the shaping of dough for producing bread and other baked goods and, in particular, it concerns devices and methods for automated knotting of dough strands to form knotted or plaited shapes.
It is known to produce various types of bread rolls and loaves in which a roll or "strand" of dough is knotted. Examples include a generally round shape formed from making a simple single knot in a strand of dough (see FIG. 22), and a more complex figure-of-eight shape (see FIG. 19). Such shapes are particularly important for producing intermediate size rolls, as well as for full-size loaves for specific markets such as the traditionally plaited "halla" loaves.
Despite the very high degree of mechanization in the baking industry, the plaiting or knotting of dough strands remains today an exclusively manual procedure. Some of the reasons for the lack of mechanization in this field will be understood from the following description of the conventional method for plaiting a figure-of-eight roll (FIGS. 1-5).
The existing procedure is divided into several steps, the first of which is bending of the right-side end 10 of a strand 12 to juxtapose it with and stick it to a straight section of the strand as shown in FIG. 1. The left-side end 14 of the strand is then passed through the loop so formed in such a manner that the left-side end 14 passes first above and then under the strand as indicated in FIG. 2. The second loop thus formed is tightened as shown in FIG. 3, and the first loop is twisted through 180.degree. to the left as indicated in FIG. 4. The left-side end 14 is pushed through the loop 16 formed by twisting as shown in FIG. 5, the left-side end being directed first above and then under the strand. This completes the plaiting procedure.
The transitions described above require operations such as: pushing of the left-side end 14 under the strand (FIG. 2) which necessitates a change of grip on the end; tightening of the left-side end 14 (FIG. 3) which causes friction of the dough strand sections and adhering thereof; and twisting of the first loop through 180 .degree. (FIG. 4), etc. These operations make the development of reliable automatic machinery very difficult.
There is therefore a need for a commercially viable device and method for automated production of knotted or plaited dough structures.